There were many advancements in many areas. I picked just a few I like.
If you want more detail, or need more background for your own personalized response instead of an existing reference, then browser search "Major Improvements of Renaissance".
Medicine: Anatomy, use of dissection for study.
Technology: Clockworks and optics, movable type printing press.
Finance: Bank Checks replacing metal coins.
Art: Lots of development and production, but not really a "breakthrough" in terms of either previous or later artistic activity.
The Renaissance saw breakthroughs in writing, arts, religion, and even accounting--but not medicine.
The Renaissance did not start or end neatly, and it didn't happen everywhere simultaneously. It was a gradual shift of thought that was most dramatically impacted by a series of events:
1305 AD: Giotto was the first major Italian painter to break away from the Byzantine style and attempt more naturalistic depictions of his subjects.
1450 Johannes Gutenberg developed Europe's first printing presses with movable metal type. Five years later, he mass-produced (well, made about 180 copies of) the Bible , which up to this point had been handwritten by monks.
1492 Columbus discovered America, triggering a new age of exploration and colonization.
1492 Double-entry accounting is invented. Every transaction is listed in two different accounts, once as a credit and once as a debit. It's much more accurate than what came before.
1517 Martin Luther nailed his ninety-five Theses to the door of the All Saints Church in Wittenberg, Germany, the first major step of the Protestant Reformation and the end of the Catholic Church's monopoly of religious influence in Western Europe.
1589 William Shakespeare wrote Two Gentlemen of Verona , his first produced play, the first of many. Cumulatively, his plays showed an inventiveness of language that upped the game of all his writing contemporaries--Shakespeare is considered the dividing line between Middle English and Modern English.
1611 The King James Version of the Holy Bible is written, in English. Up to this point, most Bibles were in Latin, and English speakers just sort of took the Catholic Church at its word about what it said. Those days were over.
I skipped a lot--I don't know that much about Leonardo or Michelangelo--but these were some of the highlights of the Renaissance.